<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        .image-slider {
            position: relative;
            display: inline-block;
        }

        .image-slider>div {
            position: absolute;
            top: 0;
            bottom: 0;
            left: 0;
            width: 50%;
            height: 290px;
            max-width: 100%;
            overflow: hidden;
            resize: horizontal;
        }

        .image-slider>div::before {
            content: '';
            position: absolute;
            bottom: 0;
            right: 0;
            width: 12px;
            height: 12px;
            padding: 5px;
            background:
                linear-gradient(-45deg, white 50%, transparent 0);
            background-clip: content-box;
            cursor: ew-resize;
        }

        .image-slider img {
            display: block;
            user-select: none;
        }
    </style>
</head>

<body>
    <div class="image-slider">
        <div>
            <img src="images/banner01.png" alt="Before" />
        </div>
        <img src="images/head01.jpg" alt="After" />
    </div>
</body>

</html>